Ship&#39;s davit



R. B STEWARD.

SH|P 'S DAVIT. APPLICATION F ILED MAR. 14. 19l9- Patented Mar. 2, 1920.

2 SHEETS-SHEET 2 7 I ZL INVENTOR 6 ATTQRNEY.

UNITED STATES PATENT OFFICE.

ROBERT BRUCE STEWARD, OF MAPLEVJOOD, NEW JERSEY, ASSIGNOR TO STEWARD DAVIT & EQUIPMENT GORPQRATIDN, OF NEW YORK, N. Y., A CORPORATION OF NEW Y RK.

SHIPS DAVIT.

Specification of Letters Patent.

Patented Mar. 2, 1920.

T0 or whom it may concern.-

Be it known that I, ROBERT BRUCE S'rnw- ARD, a citizen of the United States, and a resident of Maplewood, county of Essex, and State of New Jersey, have invented certain new and useful Improvements in Ships Davits, of which the following is a specification.

My invention relates to ships davits, and particularly to that type of clavit employing a boom or crane'movable in a vertical plane to carry a lifeboat and its load outboard and inboard of a ship. A type of ships davits to which my invention is applicable is shown in U. S. Patents Nos. 1,123,182 and 1,245,752, granted to T. H. Marten, December 24, 191 1 and November 6,1917, respectively.

One object of my invention is to relieve the means employed to move the boom or crane and its attached load, from the strains and stresses imposed by the load and to transmit them to the frame. A further object of my invention is to so improve the davit as to stabilize it against all strains and stresses to which the davit is subjected, under all conditions of weather, when the boom is moved to launch or deck the lifeboat, or is dragging the life-boat through water.

I will describe a ships davit embodying my invention and then point out the novel features thereof in claims.

In the accompanying drawings Figure 1 is a side elevation of a ships davit embodying my invention. Fig. 2 is a detail view showing in vertical cross-section, a part of the davit frame, the boom, a carriage to which it is pivotally connected and a manner of supporting the carriage on the davit frame, and embodying my invention. Fig. 3 is a detail view, also in vertical cross-section of the carriage of Fig. 2 and a portion of the operating screw. Fig. 41 is a view of a boom, partly in vertical section shown in Figs. 1 and 2, and embodying my invention. Fig. 5 is a side elevation thereof. Fig. 6 is a cross-sectional view thereof on the line 66, Fig. 5, but drawn to a larger scale. Fig. 7 is a detail view of a link and the connection for connecting the lower end of the boom with the frame. Fig. 8 is a detail view of one of the bearings for one end of the operating screw.

Referring to the drawings: 1 designates a or 'bar 19.,

'hereinbefore mentioned.

suitable frame or support; 2 a boom or crane; 3 a truck or carriage which is movable on the frame and on which the boom 2 is pivotally mounted; and 41 an operating member, here shown as a screw, for moving the truck 3 to and fro on the frame. The ends of the screw at are journaled in suitable bearings carried in brackets 10 and 11 secured to the frame. The journal in bracket 11 is shown in detail in Fig. 8 and as here shown comprises a bearing 11 of Babbitt or other anti-friction metal andtwo nuts 11 and 11 to take up the end thrusts due to the reverse turning movements of the screw 4. The lower end of the boom 2 is connected by a link 5 with the frame 1. The brackets 10 and 11 are connected by a rod The parts so far described are all well-known and operate in the manner and for the purposes set forth in the patents However, in my invention the rod or bar 12 is made to perform a function not incident to the structures disclosed in these patents.

The truck 3 carries rollers 3 suitably journaled therein and which travel on the upper member 1 of the frame. The truck also carries a pivot pin 3 the ends of which extend through the bifurcations 2*, 2 of the boom and act as a pivot therefor. The truck also carries a nut 3 through which the screw 1 passes. The nut 3 is held between two lugs or projections 3 formed on or carried by the carriage 3. Reverse turning movements are given the screw 1 by the crank P to cause the truck 8 to move to and fro on the frame.

In order to relieve the screw 1 of all the strains and stresses which might be imparted to it through the boom 2 when carry ing a load. and to deliver or transmit such strains and stresses to the frame 1, I provide bearing surfaces on the truck 3 which are preferably located above and below the screw 1, and which bearing surfaces engage the frame 1. One set of bearing surfaces are formed by flanges 3 which embrace the bar 12 comprised in the frame 1, while the lower set of bearing surfaces are formed by flanges 8 which embrace the member 1 of the frame. Babbitt-metal or other antifriction surfaces 3 are preferably provided between the sets of flanges 3 and 3 and the frame 1.

The boom 2 has bifurcations 2 and 2" as leg opposite the eye. rangement of metal a stiffer boom is obshown, and the leg 2 has a greater cross-v section .at the portion 2 than the leg 2 at its corresponding portion. The greater amount of metal therefore is in that leg of the boom which is opposite the eye 2 In practice it has been found that the line on which the forces fell, due to the load supported from the eye of the boom, is a straight line from the eye of the boom diagonally through the boom to the foot of the Therefore by this artained to take care of all pulling and lateral strains. The link 5 is also wider so as to afford a greater bearing atthe'foot of the boom. where it isconnected with the boom and with the frame by the pins 5 and 5".

its will be seen from Fig. 7 the link 5 is connected wlth the pins 5 5 atthelr ends,

the link being recessed or cut out at its ends to afford the necessary clearances for the bearing-on the frame for the pin 5 and the frame and carrying a pivot for said boom, operating means for moving said carriage to and fro on said frame, and means onthe carriage engaging the frame on opposite sides of the operating means for relieving it from and transmitting to the frame the strains and stresses due to a load carried by the boom. V

3. The combination in a ships davit, of a frame, a boom, a carriage movable on said frame and carrying a pivot for said boom, means for moving the carriage to and fro on said frame, and means located on opposite sides of the means for moving the car riage, carried by said carriage and co-acting with and having a sliding bearing on said frame.

4. The combination in a ships davit, of a frame, a boom, a carriage mounted to move to and fro on said frame and having. a

pivoted connection with the boom, means for moving the carriage to and fro on the frame, and. flanges on the carriage located above and below the said operating means for relieving said operating means and transmitting to the frame the strams and stresses due to a load carried by the boom.

In witness whereof I have signed my name to this specification, in the presence of two subscribed witnesses. f

ROBERT BRUCE STEWARD.

Witnesses: v i

C. 'LOZIER BURKE, HAMIN IRWIN. 

